Many Fuses Blown, Replacing Does Not Help
 

Hello,

I own a 98 Volvo S70, and I recently noticed that a good chunk of my fuses are somehow malfunctioning.

I bought a simple fuse tester, and it correctly lights up when used on a functioning fuse (tested on another car). However, many of my fuses test nonresponsive. Replacing the "blown" fuses does not correct the problem.

Here is the fuse information on my vehicle: 1998 S70 & V70

For my main fuse box, fuses 1-8 show responsive on my tester. Fuse 9 responds, but fuses 10-13 all show as blown. Replacing them does not resolve the issue. I am not sure how to test the relays.

For my other fuse box, fuses 2-4 and 18-36 show as blown, and replacing them does not resolve the issue?

I suspect this is a relay issue? Does anyone else have experience with massive fuse failure like this?

I have a 98 S70, and I really like to work on electrical problems, so I might be able to help you some.


The power distribution drawings in the wiring diagram will be important to look at. I have a copy that I got off volvowiringdiagrams.com. the pages are out of order but they're in there. I have adobe acrobat, so I guess I ought to fix my copy.


I want to be real clear on "fuse testing". Could you post a link to your fuse tester? Do you know what it really tests?

Fuse testers are nice, but I always pull the fuses to look at them, and/or test them with a multi-meter to see if they are good. I suspect the poblem may be with the fuse tester you are using giving false readings. If you had that many blown fuses I would suspect the car would be as dead as a doorstop.

Hi guys,

Thank you both for the replies!

Firebirdparts - here is an image of my fuse tester https://imgur.com/a/2LsVw . All it is is a nail with a lightbulb attached to a ground clip, with a wire connecting everything together. You put the clip on a ground (negative terminal, car chassis), and touch the nail to the component in question. If there is current, the bulb lights up! However, thinking about this leads me to my next question.

Everyone - Are there fuses that will only show as reading current when the car is running? I did not think to test the difference (and also my car will not start) until reading this post.

There are lots of fuses that will only have power when the ignition is on. Whether the engine is actually running probably wouldn't affect any.

Your "nail with the lightbulb" is a voltage tester and that is good. it does not test current, it tests voltage, but that is what I like.

You never mentioned what was wrong with your car. I assume you lost power to something. Also, by "main fuse box" which fuse box is that? You are talking about the one that this link refers to as "main?"
http://new.volvocars.com/ownersdocs/...98sv70_102.htm

Also, the little fuses up next to the winshield are all on different branch circuits, and a bunch of them are in line with big fuses in the "main" fuse box. They are not the problem. I am saying ignore that completely.


Assuming you do have an electrical problem, it'll be simple. they all are. I hope that makes sense. You could certainly have a problem where a large portion of the electrical system lost power. If that happened, it'll turn out to be a single bad connection.


To blow 20 fuses you'd need to have 20 ground faults. You could have that, in something like an electrical fire, or massive mechanical damage where all those wires are together under the dash. Not impossible, but much less likely than a big loss of power.

Good points! Actually the best place to start is for you to please tell us what all is not working (aside from the car not starting). Just turning the key to the "on" position should energize all of the circuits in oder for them to be operationally checked. Once we know what is not working, we can start looking for a common point (or worst case scenario, tackle and fix one issue at a time).